Please watch this video to avoid having to read my rambling and dry paragraph below.
Some PS90's even using loads well below cartridge max have issues with popping mags, miss feeds and other issues including crushing of cases. Notice I said NEAR max and not over pressure or over max. FNH increased the length of the P90 barrel to create a legal PS90. They did not though do anything to the Bolt or recoil assembly to compensate for the longer barrel, longer dwell time of the bullet in the barrel. FNH states the PS90 is a delayed blowback. It is minimally a delayed. Due to the minimal delay and the longer barrel of the PS90 chamber pressures can be higher than normal during extraction when compared to the P90 with its shorter barrel. In response to this I created a heavier rate reducer. Increasing the weight of the reducer (A hold over from the FA P90), I am compensating for the timing change of the longer PS90 barrel. As a result, the bolt slows down. This is why I state to NOT use it in conjunction with our HD recoil springs. Those springs speed the bolt back up again negating the slow down effect of the HD rate reducer. I recommend using our HD magazine catch spring with it though if you have had ongoing issues.
EA Heavy Duty Tungsten Rate Reducer 3.0oz
Factory PS90/P90 Rate reducer 1.7oz